Oxidation of Pu(III) by Nitric Acid in Tri-<i>n</i>-Butyl Phosphate Solutions. Part I. Kinetics of the Reaction and Its Effect on Plutonium Losses in Countercurrent Liquid-Liquid Extraction

Sze, Yu-Keung; Clegg, L.J.; Gerwing, Andrew Francis; Grant, G. R.

doi:10.13182/nt82-a32911

Cited by 16 publications

(10 citation statements)

References 12 publications

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“…Figure2 shows that the experimental kinetics data obtained at different Solution acidities is well described by the linear equation (13). The y-intercept at r=0 is numerically equal to ln(a/Ar,)/2.3 and the gradients of the resultant straight lines equal k'Jjx + Ki)l23.…”

Section: Dx/dt = K\{a-x)+k'^(a-x)x+k'^ia-x)x (12)mentioning

confidence: 83%

“…Data from the final reaction stage when x> K^ was used to initially estimate Ki. More accurate values of the rate constants k\ and k'^ and errors were determined by computationally solving equation (13). The results of these calculations versus [HNO3] are listed in Table 3.…”

Section: Dx/dt = K\{a-x)+k'^(a-x)x+k'^ia-x)x (12)mentioning

confidence: 99%

“…After assessing the experimental kinetic data using equation (13), the sum of the rate constants of two autocatalytic reaction routes (i.e. k'^ = k'2 + was determined.…”

Section: Effect Of Hno2 and Np(vi) On Np(iv) Oxidation Ratementioning

confidence: 99%

“…see references [8][9][10][11][12][13][14][15][16]. Since the rate of this Np(IV)-HN03 reaction is basically govemed by the Np(V) reproportionation reaction, the rate of which is proportional to [HjO]^^ [8], it is to be expected that the reaction will be catalyzed by HjO.…”

Section: Variation Of Reaction Concentration Rate With Watermentioning

confidence: 99%

“…However, by comparison the redox reactions of U, Pu and Np in organic solutions of TBP have not been studied widely (although see [8][9][10][11][12][13][14][15][16]). …”

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of the Oxidation of Neptunium(IV) by Nitric Acid in Tributyl Phosphate Solution

et al. 1997

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Kinetics / Rate equation / Tri-butyl phosphate / Neptunium(IV) / Nitrous acid / SpectrophotometryAbstract Np(IV) oxidation by nitric acid in tributyl phosphate solutions is negligible at ambient temperatures whilst at an elevated temperature it proceeds according to the stoichiometric equation (without accounting for TBP complexes):The reaction is an autocatalytic reaction that is due to the formation of more reactive (compared to HNO3) oxidants, i.e. HNO2 and Np(VI). The main contribution is made by the Np(V) reproportionation reaction. Hence Np(IV) oxidation follows the scheme: 2 Np(IV) + HNO3 = 2 Np(V) + HNO2 (slow) Np(V) + HN02 = Np(VI) + N0 (quick) Np(IV) + Np(VI) = 2 Np(V) (slow) 2 NO + HNO3 + HjO = 3 HNO2 (quick) The reaction rate is described by the equation: ^/[Np(IV)] dt <:r[Np(IV)] ^ ^Np(IV)][Np(VI)][H30]' [H.O]'" [HNOj]"where /t4 = (9.5±0.8)X 10"" min"' at 60.2°C and k" is an extremal function of the HNO3 concentration in TBP Solution with the maximum at =0.4 M HNO3; at [HNO3] = 0.2 M and T = 60.2°C, k" = (0.70 + 0.43) mol'" 1-° min"'. The activation energy of the reaction represented by k^ is 90±2 kJ/mol.

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Section: Dx/dt = K\{a-x)+k'^(a-x)x+k'^ia-x)x (12)mentioning

confidence: 83%

Section: Dx/dt = K\{a-x)+k'^(a-x)x+k'^ia-x)x (12)mentioning

confidence: 99%

“…After assessing the experimental kinetic data using equation (13), the sum of the rate constants of two autocatalytic reaction routes (i.e. k'^ = k'2 + was determined.…”

Section: Effect Of Hno2 and Np(vi) On Np(iv) Oxidation Ratementioning

confidence: 99%

Section: Variation Of Reaction Concentration Rate With Watermentioning

confidence: 99%

“…However, by comparison the redox reactions of U, Pu and Np in organic solutions of TBP have not been studied widely (although see [8][9][10][11][12][13][14][15][16]). …”

Section: Introductionmentioning

confidence: 99%

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